You could make a vaccine with a machine that synthesises DNA to an emailed sequence.

Craig Venter, who quietly sequenced the human genome using his own DNA, then made “synthetic life” by outfitting a gutted bacterium with homemade genes, says his next trick will be emailing biological molecules, using 3D biological printers. The move could revolutionise healthcare – and biological warfare.

Venter discussed the idea at last week’s Wired Health Conference in New York – although it was somewhat overshadowed by his audacious plan to sequence Martian DNA and beam the results back to Earth. Long before that sci-fi can be realised, though, bio-printers could more plausibly be used to shuttle vaccines around our planet.

This makes lots of sense. If you can email troops the 3D instructions for printing a replacement gun part , then you can email macromolecules – as long as you have a printer that can deposit a repertoire of nucleotides, sugars and/or amino acids where they belong, and link them up chemically.

You’ll need a lot of different toner cartridges to recreate the full range of biological widgets, of course. But you may not need that many for modern vaccines, made not of dead germs but of their key molecules. In fact, for DNA vaccines - which often work well in experiments but have never been commercialised, because of safety concerns – you could do it now with a machine that synthesises DNA to an emailed sequence. Proteins wouldn’t be much harder. As long as you also had the vials of sterile saline plus immunity-boosting additives to mix with the DNA or protein, and make it a vaccine.

This has game-changing implications for public health, and for biodefence. The bottleneck in fighting infectious disease, once you invent the vaccine, is getting it to people – if not, 15 kids an hour would not still be dying of measles. The blue-sky US military research organisation DARPA has long been funding efforts to make vaccines in days, rather than months.

Venter’s bio-printer, in theory, could both make and distribute a macromolecular vaccine fast. If everyone, or maybe every local clinic, had a bio-printer, a mass email of the vaccine specs should take care of a novel pandemic, or bioterror attack – or maybe even measles – in minutes. Simply print, and inject.

What could go wrong? Well, I can see the mass emailing ending up dumped in a fair number of spam filters. How do we guarantee quality control? Worse, the vaccine specs could themselves become the bioweapon. The bottleneck in biological warfare is getting the germ into the victim. Brew up a false bio-alarm, then intercept and tinker with the vaccine email, and your victims will inject it themselves. And antivirus software takes on a whole new meaning when you can spam-email Ebola or the 1918 flu.

OK, I don’t really want to pour cold water – this would be way cool if it works. If we can get the quality control right, and prevent tampering. And the prank emailing of deadly viruses. And resign ourselves to the fact that once this is available, heroin and its ilk will become as impossible to ban as spam.